Where to tell a relationship is going between friend.

I met this guy a couple of months ago (gay) through a mutual friend and from the very beginning I had a crush on him. We began to hang out in groups and would occasionally see and talk to each other at parties. Our friends eventually got word that I was seeking him and probably told him that I had a thing for him, and He even knew I did. He just went along with it and would reply to my flirting. Suddenly he stopped talking to me and began to ignore me, so being defensive I ignored him right back. Very recently we met up again and we did not say a word to one another, it was actually quite awkward between everyone since they sort of knew our "fling." It was also quite obvious we were trying to ignore each other and trying to forget we were there since we would make eye contact with each other and then turn away when caught. Our conversations were short and only happened if we truly needed something. We were really hostile to each other and frequently belittled each other. I could even sense like he was trying to make me jealous by talking about other guys in front of me so I would do the same. To get to the point I want to sort of figure out some clues as to why things might have gotten so awkward between us so quick and why we are being so stubborn towards one another, Thanks.